The Knot in the Brain

Article excerpt

READER IN PHILOSOPHY, BIRKBECK COLLEGE, UNIVERSITY OF LONDON

Philosophers since Descartes have striven to understand the connections between the material world, the body and the mind. Have brain scans brought us to the verge OF an answer?

Among the most important questions still facing human enquiry are those about the mind and its place in nature. What is mind, and what is it relation to body? I-low should we best understand our common sense concepts of such mental phenomena as belief, desire, intention, emotion, reason and memory? How does the grey matter of the brain give rise to our rich and vivid experiences of colour, sound, texture, taste and smell?

Discussion of the mind-body problem was given an especially sharp form by Descartes. He argued that everything that exists falls under the heading either of material substance or mental substance, where "substance" is a technical term denoting the most basic kind of existing stuff. He defined the essence of matter as occupancy of space, and the essence of mind as thought. But by thus making matter and mind so different, he raised the seemingly insuperable problem of how they interact. How does a bodily event like pricking oneself result in the mental event of feeling pain? How does the mental event of thinking "it's time to get up" cause the bodily event of rising from bed?

Descartes himself did not have an answer, and his successors had to resort to heroic solutions to the problem his theory had bqueathed. Their strategy was to accept dualism but to argue that mind and matter do not in fact interact, their appearance of doing so being the result of the hidden action of God. Thus for Leibniz, God acted like a clockmaker, setting the mental and material realms going in exact unison at the universe's beginning so that they thereafter act in parallel.

A much more plausible alternative, however, is monism: namely, the view that there is only one substance. Three possibilities rise to the fore. One is that there is only matter. The second is that there is only mind, The third is that there is a neutral substance which gives rise to mind and matter. Each of the three has had proponents but it is the first option--the reduction or annexation of all mental phenomena to matter--which has been most influential.

One materialist approach is the "identity theory," which asserts that mental states are literally identical with states or processes in the brain. In its earliest form, it asserted that types of mental phenomena are nothing other than types of brain occurrences, but this was quickly seen to be too sweeping, for a particular mental event (e.g. a mental image of the Eiffel tower) might in my brain activate one set of cells, while in yours another.

A football match between sociologists and physicists

On the basis of this theory, a number of philosophers currently maintain that as neuroscience advances, we will be able to eliminate the old-fashioned and imprecise mental vocabulary we standardly use. Research in neurology and cognitive science have built an overwhelming case for accepting a very intimate relation between mental and neurological phenomena. …